1. Field of the Invention
The present invention relates to pliers for suction cup capable of effectively removing from an eyeglass lens a suction cup for using to mount the eyeglass lens on a lens grinding apparatus which grinds the eyeglass lens.
2. Description of the Prior Art
Conventionally, there is known a lens grinding apparatus which grinds the periphery of an unprocessed circular eyeglass lens (blank lens) into a lens configuration (edge shape) of an eyeglass frame. In the lens grinding apparatus, the eyeglass lens is adapted to grind by a grinder into an edge shape of the eyeglass frame with rotation of a pair of lens rotated shafts for holding the eyeglass lens.
Generally, there is used a suction cup 20 for holding an eyeglass lens 30 to lens rotated shafts (not shown) as shown in FIG. 7.
The suction cup 20 comprises a lens holding portion 21 made of a resilient member of a hard rubber and so on and a mounting base 22 formed integrally with the lens holding portion 21.
The lens holding portion 21 has an adhesive surface 21a to which a double-stick tape 23 having both adhesive surfaces is adhered. The double-stick tape 23 acts to adhere the adhesive surface 21a of the lens holding portion 21 to a curved surface 31 of the eyeglass lens 30.
The mounting base 22 is, also, formed to project in a rod-like manner from the center of the lens holding portion 21. Herein, the mounting base 22 has at its outer periphery an annular concave groove 22a to fit a rotated shaft (not shown) of the lens grinding apparatus therein.
Note that the adhesive surface 21a of the lens holding portion 21 may be adsorbed to the curved surface 31 of the eyeglass lens 30 by any adsorbed means to secure the suction cup 20 to the eyeglass lens 30 with adsorption force of the adsorbed means.
To hold the eyeglass lens 30 between the lens rotated shafts by use of the suction cup 20, one adhesive surface of the double-stick tape 23 is first adhered to the adhesive surface 21a of the lens holding portion 21.
The other adhesive surface of the double-stick tape 23 on which the lens holding portion 21 is mounted is adhered to the curved surface 31 of the eyeglass lens 30 to secure the lens holding portion 21 to the eyeglass lens 30 with an adhesive force of the double-stick tape 23.
Next, the mounting base 22 of the suction cup 20 is inserted into a shaft mounting hole (not shown) provided in an end surface of one of the lens rotated shafts.
A rubber lens retainer (not shown) provided on the other lens rotated shaft is held on the eyeglass lens 30 to hold the eyeglass lens between the pair of lens rotated shafts.
On the other hand, to take out the eyeglass lens 30 from the lens rotated shafts after the eyeglass lens 30 is ground in a predetermined shape, the suction cup 20 is first disengaged from the shaft mounting hole of one lens rotated shaft with the suction cup 20 being adhered to the eyeglass lens 30 to take the eyeglass lens 30 and suction cup 20 out of the lens rotated shafts.
One adhesive surface of the double-stick tape 23 adhered to the adhesive surface 21a of the lens holding portion 21 is then removed from the curved surface 31 of the eyeglass lens 30 by pinching the mounting base 22 of the suction cup 20 by means of a pair of flat pinching portions of a conventional pliers.
However, in the conventional pliers used, pinching the mounting base by the flat pinching portions causes the mounting base 22 formed with a resilient member of rubber to deform to slip the pinching portions along the mounting base without gripping it. Since deformation of the mounting base 22 causes the mounting base to remove from the pinching portions, it is difficult to firmly grip the mounting base.
Since whole the flat pinching portions, also, contact with the mounting base, a contact area between the pinching portions and mounting base is large to disperse a pinching force. Accordingly, there is a defect that it is difficult to separate the lens holding portion from the eyeglass lens even though a strong force is applied on the mounting base 22.
It is an object of the present invention to provide pliers for suction cup capable of easily removing a suction cup from an eyeglass lens.
To accomplish the object as mentioned above, pliers according to the present invention are adapted to use to remove from an eyeglass lens a suction cup having a lens holding portion for holding the eyeglass lens and a mounting base formed integrally with the lens holding portion.
The pliers comprise first and second pinching portions relatively movable close and apart to each other for pinching the mounting base, opposed surfaces formed on the first and second pinching portions to oppose the mounting base and an engaged convex portion provided on at least one of the opposed surfaces of the first and second pinching portions to contact with the mounting base in one embodiment.
The engaged convex portion extends toward the opposed surface of the other pinching portion and is contactable with a portion of the mounting base.
In one example, a surface of the engaged convex portion contacting with the mounting base is flat.
In the other example, the surface contacting with the mounting base is arcuate.
In the other embodiment, an engaged convex portion is provided on each of the opposed surfaces of the first and second pinching portions.
The engaged convex portion provided on one opposed surface extends toward the other opposed surface. These engaged convex portions act to pinch a portion of the mounting base.
In one example, surfaces of the engaged convex portion contacting with the mounting base are flat.
In the other example, the surfaces contacting with the mounting base are arcuate.
The opposed surfaces of the first and second pinching portions are arcuate in one example.